Personalizing non-small cell lung cancer treatment through patient-derived xenograft models: preclinical and clinical factors for consideration.

PURPOSE: In the pursuit of creating personalized and more effective treatment strategies for lung cancer patients, Patient-Derived Xenografts (PDXs) have been introduced as preclinical platforms that can recapitulate the specific patient's tumor in an in vivo model. We investigated how well PDX models can preserve the tumor's clinical and molecular characteristics across different generations. METHODS: A Non-Small Cell Lung Cancer (NSCLC) PDX model was established in NSG-SGM3 mice and clinical and preclinical factors were assessed throughout subsequent passages. Our cohort consisted of 40 NSCLC patients, which were used to create 20 patient-specific PDX models in NSG-SGM3 mice. Histopathological staining and Whole Exome Sequencing (WES) analysis were preformed to understand tumor heterogeneity throughout serial passages. RESULTS: The main factors that contributed to the growth of the engrafted PDX in mice were a higher grade or stage of disease, in contrast to the long duration of chemotherapy treatment, which was negatively correlated with PDX propagation. Successful PDX growth was also linked to poorer prognosis and overall survival, while growth pattern variability was affected by the tumor aggressiveness, primarily affecting the first passage. Pathology analysis showed preservation of the histological type and grade; however, WES analysis revealed genomic instability in advanced passages, leading to the inconsistencies in clinically relevant alterations between the PDXs and biopsies. CONCLUSIONS: Our study highlights the impact of multiple clinical and preclinical factors on the engraftment success, growth kinetics, and tumor stability of patient-specific NSCLC PDXs, and underscores the importance of considering these factors when guiding and evaluating prolonged personalized treatment studies for NSCLC patients in these models, as well as signaling the imperative for additional investigations to determine the full clinical potential of this technique.

Identificação e Caracterização Funcional de Alterações Genéticas em Sarcomas Pleomórficos Indiferenciados e Fusocelulares / Identification and Functional Characterization of Genetic Alterations in Undifferentiated and Fusocellular Pleomorphic Sarcomas

Os sarcomas de partes moles (SPM) são tumores malignos derivados de células mesenquimais, com grande capacidade de formar metástases e geralmente apresentam elevada resistência à terapia. Formam um grupo extremamente heterogêneo com mais de 100 subtipos tumorais, como os sarcomas pleomórficos indiferenciados (SPI) e os sarcomas fusocelulares (SF). Em conjunto, esses dois subgrupos não compartilham semelhanças morfológicas com os outros subtipos. Adicionalmente, carecem de informações moleculares que auxiliem tanto no diagnóstico quanto no prognóstico da doença. O objetivo deste trabalho foi estabelecer e caracterizar modelos pré-clínicos de SPI e SF baseados em Patient-derived xenografts (PDX) e organoids (PDO) para definir uma plataforma de estudos destes tumores e avaliar o potencial de alvos moleculares específicos. Utilizando amostras de 11 pacientes, foi possível estabelecer oito PDX de SPI ou SF. O estabelecimento de organóides de sarcoma se mostrou desafiador para amostras tumorais oriundas diretamente de pacientes ou de PDX e após testarmos diferentes protocolos, conseguimos obter organóides de culturas primárias tumorais. Os organoides e os PDXs gerados foram caracterizados por IHQ e foi possível observar a preservação das características moleculares. Para a caracterização genética, realizamos o sequenciamento de exoma de um conjunto de oito amostras (paciente/PDX/cultura celular) para identificação das principais alterações somáticas. Por fim, padronizamos o ensaio de citotoxicidade à doxorrubicina em três culturas primárias de SPI e SF.

Soft tissue sarcomas (STS) are malignant tumors derived from mesenchymal cells, with a great capacity to form metastases and generally show high resistance to therapy. They form an extremely heterogeneous group with more than 100 tumor subtypes, such as undifferentiated pleomorphic sarcoma (UPS) and fusocellular sarcomas (SS). Taken together, these two subgroups do not share morphological similarities with the other subtypes. Additionally, they lack molecular information that helps both in the diagnosis and prognosis of the disease. The objective of this work was to establish and characterize preclinical models of UPS and SS based on Patient-derived xenografts (PDX) and organoids (PDO) to define a platform for studies of these tumors and to evaluate the potential of specific molecular targets. Using samples from eleven patients, it was possible to establish eight PDX of UPS and SS. The establishment of sarcoma organoids proved to be challenging for tumor samples derived directly from patients or from PDX and after testing different protocols, we were able to obtain organoids from primary tumor cultures. The generated organoids and PDXs were also characterized by IHC and immunofluorescence with sarcoma marker proteins and it was also possible to observe the preservation of molecular characteristics. For genetic characterization, we performed exome sequencing of a set of eight samples (patient/PDX/cell culture) to identify the main somatic alterations. Finally, we standardized the doxorubicin cytotoxicity assay in three primary cultures of SPI and SF.

Anti-tumor activity of the MDM2-TP53 inhibitor BI-907828 in dedifferentiated liposarcoma patient-derived xenograft models harboring MDM2 amplification.

PURPOSE: Dedifferentiated liposarcoma (DDLPS) is a soft tissue malignancy characterized by amplification of the mouse double minute 2 homolog (MDM2) gene. MDM2 is a negative regulator of tumor protein 53 (TP53). We tested the in vivo efficacy of BI-907828, a small molecule inhibitor of the MDM2-TP53 interaction, in two DDLPS patient-derived xenografts (PDX). METHODS: Partially immunodeficient mice were bilaterally engrafted with UZLX-STS3 (n = 24) and UZLX-STS5 (n = 24) human DDLPS tissue harboring MDM2 amplifications. Mice were grouped as follows: (a) vehicle (0.5% hydroxyethylcellullose) 10 ml/kg daily per os (p.o.); (b) doxorubicin 5 mg/kg weekly intraperitoneally (i.p.); (c) BI-907828 2.5 mg/kg daily p.o. and (d) BI-907828 10 mg/kg daily p.o. The treatment lasted for 15 days, all mice treated with BI-907828 were followed for 37 days post-treatment. Efficacy was assessed by tumor volume and histopathological evaluation. RESULTS: The 15-day treatment with 2.5 mg/kg and 10 mg/kg BI-907828 significantly inhibited tumor growth in UZLX-STS5 and -STS3 (p < 0.0001 compared to control for both models). All UZLX-STS5 and -STS3 tumors treated with BI-907828 decreased in size during treatment, and BI-907828-treated UZLX-STS5 tumors even disappeared completely. During the follow-up period, no tumor regrowth was observed in the UZLX-STS5 model and both doses of BI-907828 led to a pathological complete response, whereas a dose-dependent regrowth was seen in the UZLX-STS3 model. CONCLUSION: BI-907828 showed significant anti-tumor activity in DDLPS PDX harboring MDM2 amplifications, providing a strong rationale for early clinical testing of BI-907828 in a DDLPS patient population.